|
The Zenith DA 3520, which is also known as the LG DA 3520 in some countries, is a
DVD Receiver. It contains a DVD player that also plays audio CD's and MP3 from
CD, CD-R or CD-RW media (D2D+) as well as an AM/FM radio receiver
(A2D) and inputs for 2 external devices
(A2D). The system can be operated in a 6-channel 5.1 mode when your program
material is encoded in the DTS or Dolby Digital 5.1 format. It has a digital signal
processing section with a Dolby Pro Logic surround decoder that can take normal
stereo program material and render it in a pseudo 5.1 format. Or it can add digital
reverberation to the program material and deliver the
additional ambience through the rear speakers.
| Audio Modes |
|
| DTS |
Plays 5.1 material encoded in the DTS
format |
| Dolby Digital |
Plays 5.1 material encoded in the Dolby Digital format |
| Dolby Pro Logic |
Dolby Pro Logic derives five-channel surround from
stereo material |
| Theatre Hall 1 |
Creates the ambience of a large listening room with adjustable
delay |
| Theatre Hall 2 |
Creates the ambience of a different listening room with adjustable
delay |
| PCM (stereo) |
Plays ordinary stereo CD's thru the front left and front right
speakers |
| MP3 (stereo) |
Plays ordinary MP3 files thru the front left and front right
speakers |
The system is equipped with a
two-way speaker system consisting of a sub woofer for low frequencies, and five
satellite speakers for the low midrange and higher frequencies. Three are for the
front sound stage (Left Center and Right) and two are for the rear stage (Left Rear
and Right Rear). The speakers are fed by six channels of digital power
amplification. The five surround channels are rated at 30 watts per channel. The
subwoofer channel is rated at 30 watts as well.
The system comes equipped with a full-function IR remote control that can be used
to operate every function and control on the DA 3520 except the Disk Eject button.
The DA 3520 is a unique piece of audio equipment. It is the first mass-produced
devices with a purely digital audio signal path (D2D+) employing Apogee
Technologies DDX Digital Amplifier Chipset. Just 4 chips deliver over 180 watts of
power in the form of six 30 watt digital power amplifiers.
You may remember Apogee Acoustics legendary ribbon speaker systems (Diva,
Duetta, Capiler, Scintilla, and Full Range). The designer of these speaker systems and
company founder of Apogee Acoustics, Mr. Leo Spiegel, also designed the Apogee
DDX Amplifier technology and founded Apogee Technologies as well.
Digital Amplifiers don't sound like Transistor or Tube driven Linear Power
Amplifiers. Its hard to describe the sound of a purely digital signal chain. That's
because it doesn't sound like anything at all. Absolutely nothing is added to or
subtracted from the signal.
In an analog system, every stage of every analog device in the signal path contributes
to the distortion of the signals passing thru the chain by adding its own artifacts to
the signal. You can reduce the distortion and artifacts in analog circuitry with
careful designs and ultra high part tolerances (hand picked parts) but you can never
eliminate them completely.
Let's take a look at an average analog signal chain
- The digital signal is extracted from the surface of a CD in the CD player.
- The digital signal is then converted to an analog signal by a D/A converter located in the CD Player.
- The analog signal then goes to the preamp where it goes through one or more stages of
amplification and possibly tone control or equalization stages and usually an output stage.
- The analog signal then goes to a power amplifier which has several stages of circuitry to amplify the signal to a level that will drive a loudspeaker.
- The analog output of the power amplifier is finally fed to the loudspeaker.
Let's take a look at the digital signal chain in the DA 3520.
- The digital signal is extracted from the surface of a CD in the CD player.
- The digital signal passes thru the DSP (Digital Signal Processor) circuitry.
- The digital signal is fed into the Digital Power Amplifier Chipset.
- The analog output of the amplifier is fed to the loudspeaker.
Possible sources of signal degradation in the analog signal chain
- Distortion and other artifacts could be introduced in the CD Players D/A converter.
- Distortion and other artifacts could be introduced in the CD player output stage.
- Distortion and other artifacts could be introduced in every stage of the preamp.
- Distortion and other artifacts could be introduced in every stage of the power amplifier.
Possible sources of signal degradation in the digital signal chain
- NONE in the DVD / CD player (all digital).
- NONE in the DSP (Digital Signal Processor) unless you are adding audio effects.
- NONE in the Digital Power Amplifier Chipset (all digital).
Digital signals, by design, can pass through any amount of electronic circuitry completely
unscathed and intact. It's absolutely impossible to confuse a 0 and a 1 in a digital
system. All this lovely accuracy without taking any of the costly measures required
to make a low distortion analog circuit. Sorry, but a perfect digital clone beats a
slightly distorted signal any day hands down. If the signal you are listening to is
digital already (from a digital source like CD / DVD / DSAT / MP3 etc) you would
probably be best served by keeping the signal digital all the way to the speaker
terminals (D2D). Digital Amplifiers with digital inputs
(D2D) have distinct
advantages over every Analog Amplifier (A2A). Digital Amplifiers with digital
inputs (D2D) do not need any analog stages and the tiny amount of signal
degradation inherent in every stage of all analog circuitry. Keeping the signal digital
insures that absolutely no distortion or artifacts will be added to the signal.
The Apogee DDX chip set has a unique 3 state (ternary) output while most digital
amplifiers have 2 possible output states (binary). You can not easily measure the
effect of the damped ternary design employed in the Apogee DDX system with
conventional test methodologies. But you can certainly hear the difference when you
hook it up to a loudspeaker. Its effect is an improved accuracy (lower distortion) on
most types of speakers. More...
It's like power brakes being briefly applied the speaker diaphragm on occasion.
This is accomplished by shorting the speaker's voice coil
momentarily. If the loudspeaker diaphragm and voice coil are not in the correct position the short on the voice
coil and the diaphragm and voice coils own inertia will cause the speaker to produce an inverse
correction voltage. This will power assist the speakers voice coil and diaphragm
in arriving at the correct position
thereby following the signal more accurately and reducing distortion.
The damping that this provides helps to reduce the natural
effects of inertia on the mass of the moving parts of the
loudspeaker, namely the speaker diaphragm and voice coil
thereby, reducing overshoot and undershoot.
How It Sounds
The digital power amplifiers built in to the DA 3520 never clip even at maximum volume. This may seem a bit strange to some people because
many analog amplifiers
produce clipping and increased distortion and grit at or near maximum levels.
The system produced a very transparent and open sounding high end, a warm
midrange and a very tight and accurate bass unlike any other piece of
consumer electronic equipment I have ever heard. It had None of the grit of a
transistorized system yet it had all the warmth of a tube system with superior
clarity. The bass was extremely tight and accurate.
Now that digital amplifier chips with digital inputs (D2D) are a market reality
it's
possible to remove that last barrier to a purely digital signal path, the analog power
amplifier. Digital amplifier chips are available and at good price points. The low
cost of Digital Amplifier chips along with savings that are realized by their
efficiency
(lower power supply and cooling costs) means audiophile quality levels will be
showing up in lower priced mass produced consumer products like the DA 3520
thus moving the masses into the high audio quality neighborhood once only
inhabited by wealthy audiophiles. Digital Amplifier chips give an audible quality
boost to any product employing them and increasing its perceived value.
Factors Contributing To the DA 3520's Phenomenal Sound Quality
- Pure digital (D2D+) signal path for material coming from a DVD / CD / MP3 disk
- Apogee DDX Amplification on board
- DDX Damped Ternary design reduces speaker distortion
- 2 Way Bi-Amped design has no speaker level crossover networks
|
